Use of Cytokines and Mitogens to Inhibit Pathological Immune Responses

ABSTRACT

The invention is generally related to methods of treating autoimmune diseases, including both antibody-mediated and cell-mediated disorders.

CROSS REFERENCE

This application is a continuation of U.S. Ser. No. 11/507,908, filedAug. 21, 2006, which is a continuation of U.S. Ser. No. 10/650,157,filed Aug. 27, 2003, which is a continuation of U.S. Ser. No.10/028,944, filed Dec. 12, 2001, now U.S. Pat. No. 6,797,267, which is acontinuation of Ser. No. 09/564,436, filed May 4, 2000, now U.S. Pat.No. 6,358,506, which claims the benefit of the filing date of U.S. Ser.No. 60/132,616, filed May 5, 1999, and is a continuation in part of U.S.Ser. No. 09/186,771, filed Nov. 5, 1998, now U.S. Pat. No. 6,228,359,which claims the benefit of the filing date of U.S. Ser. No. 60/064,507,filed Nov. 5, 1997.

FIELD OF THE INVENTION

The field of the invention is generally related to methods of treatingautoimmune diseases, including both antibody-mediated and cell-mediateddisorders.

BACKGROUND OF THE INVENTION

Autoimmune diseases are caused by the failure of the immune system todistinguish self from non-self. In these diseases, the immune systemreacts against self tissues and this response ultimately causesinflammation and tissue injury. Autoimmune diseases can be classifiedinto two basic categories: antibody-mediated diseases such as systemiclupus erythematosus (SLE), pemphigus vulgaris, myasthenia gravis,hemolytic anemia, thrombocytopenia purpura, Grave's disease, Sjogren'sdisease and dermatomyositis; and cell-mediated diseases such asHashimoto's disease, polymyositis, disease inflammatory bowel disease,multiple sclerosis, diabetes mellitus, rheumatoid arthritis, andscleroderma.

In many autoimmune diseases, tissue injury is caused by the productionof antibodies to native tissue. These antibodies are calledautoantibodies, in that they are produced by a mammal and have bindingsites to the mammal's own tissue. Some of these disorders havecharacteristic waxing and waning of the amount of circulatingautoantibodies causing varying symptoms over time.

Of the different types of antibody-mediated autoimmune disorders, SLE isa disorder that has been well studied and documented. SLE is a disorderof generalized autoimmunity characterized by B cell hyperactivity withnumerous autoantibodies against nuclear, cytoplasmic and cell surfaceantigens. This autoimmune disease has a multifactorial pathogenesis withgenetic and environmental precipitating factors (reviewed in Hahn, B.H., Dubois' Lupus Erythematosus, 5th Ed. (1997), pp. 69-76 (D. J.Wallace et al. eds., Williams and Wilkins, Baltimore)). Among thenumerous lymphocyte defects described in SLE is a failure of regulatoryT cells to inhibit B cell function (Horwitz, D. A., Dubois' LupusErythematosus, 5th Ed. (1997), pp. 155-194 (D. J. Wallace et al. eds.,Williams and Wilkins, Baltimore)). Sustained production of polyclonalIgG and autoantibodies in vitro requires T cell help (Shivakumar, S. etal. (1989), J Immunol 143:103-112).

Regulatory T cells can down-regulate antibody synthesis by lytic orcytokine-mediated mechanisms. The latter involve transforming growthfactor-beta (TGF-β) and other inhibitory cytokines (Wahl, S. M. (1994),J Exp Med 180:1587-190). Circulating B lymphocytes spontaneouslysecreting antibodies are increased in patients with active SLE (Klinman,D. M. et al. (1991), Arthritis Rheum 34:1404-1410).

Clinical manifestations of SLE include a rash (especially on the face ina “butterfly” distribution), glomerulonephritis, pleurisy, pericarditisand central nervous system involvement. Most patients are women, and arerelatively young (average age at diagnosis is 29).

The treatment of SLE depends on the clinical manifestations. Somepatients with mild clinical symptoms respond to simple measures such asnonsteroidal anti-inflammatory agents. However, more severe symptomsusually require steroids with potent anti-inflammatory andimmunosuppressive action such as prednisone. Other strongimmunosuppressive drugs which can be used are azathioprine andcyclophosphamide. The steroids and other immunosuppressive drugs haveside effects due to the global reduction of the mammal's immune system.There is presently no ideal treatment for SLE and the disease cannot becured.

Currently, considerable attention has been focused on the identity ofgenes which enhance the susceptibility or resistance to SLE, theidentification of antigenic determinants that trigger the disease, themolecular mechanisms of T cell activation which results in survival orapoptosis, cytokines which determine T cell function, and the propertiesof the autoantibody-forming B cells. Many examples of T celldysregulation in SLE have been described (reviewed in Horwitz, D. A. etal., Dubois' Lupus Erythematosus, 5th Ed. (1997), pp. 83-96 (D. J.Wallace et al. eds., Williams and Wilkins, Baltimore). Although it iswell recognized that the primary role of certain lymphocytes is todown-regulate immune responses, progress in elucidating the identity andmechanisms required for generation of these cells has been slow.

Interleukin-2 (IL-2) has previously been considered to have an importantrole in the generation of antigen non-specific T suppressor cells.Anti-IL-2 antibodies given to mice coincident with the induction ofgraft-versus-host-disease resulted in several features of SLE (Via, C.S. et al. (1993), International Immunol. 5:565-572). Whether IL-2directly or indirectly is important in the generation of suppression hasbeen controversial (Fast, L. D. (1992), J. Immunol. 149:1510-1515;Hirohata, S. et al. (1989), J. Immunol. 142:3104-3112; Baylor, C. E.(1992), Advances Exp. Med. Biol. 319:125-135). Recently, IL-2 has beenshown to induce CD8+ cells to suppress HIV replication in CD4+ T cellsby a non-lytic mechanism. This effect is cytokine mediated, but thespecific cytokine has not been identified (Kinter, A. L. et al. Proc.Natl. Acad. Sci. USA 92:10985-10989; Barker, T. D. et al. (1996), J.Immunol. 156:4478-4483). T cell production of IL-2 is decreased in SLE(Horwitz, D. A. et al. (1997), Dubois' Lupus Erythematosus, 5th Ed.(1997), pp. 83-96, D. J. Wallace et al. eds., Williams and Wilkins,Baltimore).

CD8+ T cells from subjects with SLE sustain rather than suppresspolyclonal IgG production (Linker-Israeli, M. et al. (1990), ArthritisRheum. 33:1216-1225). CD8+ T cells from healthy donors can be stimulatedto enhance antibody production (Takahashi, T. et al. (1991), Clin.Immunol. Immunopath. 58:352-365). However, neither IL-2 nor CD4+ Tcells, by themselves, were found to induce CD8+ T cells to developstrong suppressive activity. When NK cells were included in thecultures, strong suppressive activity appeared (Gray, J. D. et al.(1994) J. Exp. Med. 180:1937-1942). It is believed that the contributionof NK cells in the culture was to produce transforming growth factorbeta (TGF-β) in its active form. It was then discovered thatnon-immunosuppressive (2-10 pg/ml) concentrations of this cytokineserved as a co-factor for the generation of strong suppressive effectson IgG and IgM production (Gray, J. D. et al. (1994) J. Exp. Med.180:1937-1942). In addition, it is believed that NK cells are theprincipal source of TGF-β in unstimulated lymphocytes (Gray, J. D. etal. (1998), J. Immunol. 160:2248-2254). TGF-βs are a multifunctionalfamily of cytokines important in tissue repair, inflammation andimmunoregulation (Massague, J. (1980), Ann. Rev. Cell Biol. 6:597).TGF-β is unlike most other cytokines in that the protein released isbiologically inactive and unable to bind to specific receptors (Sporn,M. B. et al. (1987) J. Cell Biol. 105:1039-1045). The latent complex iscleaved extracelluarly to release active cytokine as discussed below.The response to TGF-β requires the interaction of two surface receptors(TGF-β-R1) and TGF-β-R2) which are ubiquitously found on mononuclearcells (Massague, J. (1992), Cell 69:1067-1070). Thus, the conversion oflatent to active TGF-β is the critical step which determines thebiological effects of this cytokine.

It was found that SLE patients have decreased production of TGF-β1 by NKcells. Defects in constitutive TGF-β produced by NK cells, as wellinduced TGF-β were documented in a study of 38 SLE patients (Ohtsuka, K.et al. (1998), J. Immunol. 160:2539-2545). Neither addition ofrecombinant IL-2 or TNF-alpha, or antagonism of IL-10 normalized theTGF-β defect in SLE. Decreased production of TGF-β in SLE did notcorrelate with activity of disease and, therefore, may be a primarydefect.

Systemic administration of TGF-β, IL-2, or a combination of both canlead to serious side effects. These cytokines have numerous effects ondifferent body tissues and are not very safe to deliver to a patientsystemically. It is, therefore, an object of the invention to providemethods and kits for treating mammalian cells that are responsible forcontrolling the regulation of autoantibodies to increase the populationof cells that down regulate auto-antibody production.

SUMMARY OF THE INVENTION

In accordance with the objects outlined herein, the present inventionprovides methods for inhibiting immune responses in a sample of ex vivoperipheral blood mononuclear cells (PBMCs) comprising adding anregulatory composition to the cell population. In an additional aspect,the present invention provides methods for treating an autoimmunedisorder in a patient. The methods comprise removing peripheral bloodmononuclear cells (PBMC) from the patient and treating the cells with anregulatory composition for a time sufficient to suppress inflamation andtissue injury. In particular, the methods of the present inventionsuppress antibody production or induce cells to down regulate antibodyproduction and enhance cell mediated immune responses in patients withantibody mediated autoimmune diseases. The treated cells are thenreintroduced to the patient, with a resulting amelioration of theautoimmune symptoms. The regulatory composition preferably comprisesTGF-β and agents which enable T cells to respond to TGF-β.

In an additional aspect, the present invention provides methods fortreating cell-mediated autoimmune diseases. The methods compriseremoving peripheral blood mononuclear cells (PBMC) from the patient andtreating the cells with an regulatory composition for a time sufficientto suppress tissue injury by immune cells. The treated cells are thenreintroduced to the patient, with a resulting amelioration of theautoimmune symptoms. The regulatory composition preferably comprisesTGF-β and agents which enable T cells to respond to TGF-β.

In an additional aspect, the invention provides kits for the treatmentof an autoimmune disorder in a patient. The kits comprise a celltreatment container adapted to receive cells from a patient with anantibody-mediated autoimmune disorder or a cell-mediated disorder and atleast one dose of an regulatory composition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows that incubation of SLE patients PBMC with IL-2 and TGF-βdecreases spontaneous immunoglobulin production. PBMC (2×10⁵/well) werecultured in AIM-V serum free medium with or without IL-2 (10 U/ml) andTGF-β (10 pg/ml). After 3 days, the wells were washed three times andfresh AIM-V medium added. Supernatants were collected from the wellsafter a further 7 days and IgG content determined by an ELISA.

FIG. 2 shows that both IL-2 and TGF-β significantly decrease spontaneousIgG production. The values represent the mean±SEM of IgG (μg/ml)produced by the 12 SLE patients PBMC cultured as described in legend toFIG. 1 except some cells were also incubated with IL-2 (10 U/ml) orTGF-β (10 pg/ml) only.

FIGS. 3A and 3B show that anti-TGF-β can reverse the effects of IL-2.SLE patients PBMC was cultured for three days in the presence (solidbars) or absence (spotted bars) of IL-2 (10 U/ml). Included in thesecultures was medium, anti-TGF-β (10 μg/ml) or control mouse IgG1 (10μg/ml). After 3 days the wells were washed and fresh AIM-V medium added.Supernatants were collected after a further seven days and assayed forIgG (FIG. 3A) or anti-nucleoprotein (NP) (FIG. 3B) content by an ELISA.

FIGS. 4A, 4B and 4C depict regulatory effects of CD8+ T cells onantibody production. (A) Synergism between NK cells and CD8+ cells inthe suppression of IgG production in a healthy subject. CD4+ cells and Bcells were stimulated with anti-CD2 and the effects of CD8+ cells and NKcells were examined. The combination of NK and CD8+ cells markedlyinhibited anti-CD2 induced IgG production we previously reported (Gray,J. D. et al. (1998), J Immunol 160:2248-2254; Gray, J. D. et al. (1994),J Exp Med 180:1937-1942). (B) NK cells and CD8+ cells enhance IgGsynthesis in SLE. CD4+ cells from a patient with active SLE and restingB cells from a healthy subject were stimulated with anti-CD2.Enhancement of IgG production by SLE CD8+ cells was markedly increasedby the addition of NK cells. (C) Cytokine normalization of CD8+ T cellfunction in SLE. In parallel with the study shown in FIG. 4B, CD4+ Tcells from this patient were stimulated with anti-CD2 in the presence orabsence of CD8+ T cells. IL-2 (10 U/ml) and/or TGF-β (2 pg/ml) was addedwhere indicated. These cytokines abolished the helper effects of theseCD8+ cells and enabled them to inhibit IgG production by 75%.

FIGS. 5A and 5B depict the lymphocyte production of TGF-β1 byunstimulated and anti-CD2 stimulated cells. PBL from healthy donors andpatients of SLE and RA were added to microtiter plates at 1×10⁵/well.Some wells received the anti-CD2 mAbs GT2 (1:40) and T11 (1:80). After 2days at 37

C., supernatants were harvested and assayed for active and total TGF-β1.Significant p values are indicated.

FIGS. 6A and 6B depict the effects of TGF-β on T cell production ofTNF-α and IL-10. Purified T cells (1×10⁵ cells/well) in serum free AIM Vmedium were added to flat bottomed microwells and stimulated with a lowdose (0.5 μg/ml) or high dose (5 μg/ml) of Con A with or without IL-2(10 U/ml) in the presence or absence of TGF-β (1 ng/ml). Supernatantswere collected at 2 days and 5 days and tested for TNF-α and IL-10 byELISA. Maximal production of TGF-β was found at 2 days and for IL-10 at5 days. TGF-β abolished IL-10 production and up-regulated TNF-αproduction.

FIGS. 7A and 7B show that TNF-α is an essential intermediate for thegeneration of regulatory T cells by TGF-β. Purified CD8+ cells wereincubated overnight with Con A (2.5 μg/ml), II-2 (10 U) and TGF-β (10pg/ml). After washing these cells were added to CD4+ B cells andstimulated with anti-CD2. To some wells anti-TNF-α antibody (10 μg/ml)or isotype control antibody (10 μg/ml) was included. After 7 days,supernatants were evaluated for IgG content by an ELISA. The regulatoryactivity of conditioned CD8+ cells was reversed by anti-TNF-α.

FIGS. 8A-8C depict that enhanced production of Th1 cytokines by TGF-βprimed T cells is dependent upon TNF-α. Purifed naive T cells werecultured with Con A (5 μg/ml) an IL-2 (10 U/ml) in the presence of TGF-β(1 ng/ml). Some wells also received neutralizing anti-TNF-α antibody (10μg/ml) or isotype control antibody (10 μg/ml). After 5 days of culture,the cells were washed and replated at 1×10⁵ cells/well in fresh medium.The next day they were restimulated with Con A and IL-2 for 6 hours and,in the presence of brefeldin A (10 μg/ml), the cells were stained forCD8 and the cytokines indicated. The percentage of CD8+ and CD8− cellsexpressing TNF-α, IL-2 and IFN-γ is shown. Note that neutralization ofTNF-α in primary cultures abolished the enhancing effects of TGF-β onproduction of Th1 cytokines.

FIGS. 9A-9C depict the effect of TGF-β in generating suppressors ofcytotoxic T cell activity. T cells from donor A prepared by E rosettingwere divided into two portions. One portion was used as responders foran allogeneic mixed lymphocyte reaction (allo-MLR). The other portionwas used to prepare the T cell subsets indicated by negative selectionafter staining the cells with appropriate monoclonal antibodies andremoving the stained cells using immunomagnetic beads. The responder Tcells were mixed with stimulator cells from donor B (irradiated T celldepleted peripheral blood mononuclear cells) and cultured for 5 days togenerate killer cells. Controls consisted of the T cell subsets culturedfor 5 days with or without stimulator cells. Afterwards, the cells werewashed, counted and used to assess allo-cytotoxic T cell activity. Theresponder cells from donor A were mixed with chromium labeledlymphoblasts from donor B in the effector to target cell ratios shownand chromium release was measured in a standard 4 hour assay (opensquares). T cells subsets cultured with stimulators were added in aratio of 1 regulatory cell per 4 responder cells (open circles). T cellsubsets cultured with stimulators with TGF-beta are shown as closedcircles. In all experiments, the maximal effects of TGF-beta were onnaive CD4 CD45RA+ CD45RO− cells.

FIGS. 10A and 10B depict the effect of CD4 cells primed with TGF-beta onallo-cytotoxic T lymphocyte (CTL) activity. The addition of CD4 CD45RAcells that had been cultured for 5 days without stimulators had noeffect on CTL activity (result not shown). Culturing these T cells withstimulator cells resulted in modest to moderate suppressive activity. Inall experiments, culture of these T cells with TGF-beta 1 ng/ml markedlysuppressed, or abolished allo-CTL activity.

FIGS. 11A and 11B demonstrate that regulatory T cells require cellcontact to inhibit CTL activity. Regulatory CD4 cells were prepared fromCD4 CD45RA cells cultured with TGF-beta as described above. Some ofthese cells were mixed with responder and chromium-labeled target cells,while others were separated from the killer cells by a membrane.Inhibition of cytotoxic T lymphocyte activity (CTL) was only observedwhen the regulatory T cells were in direct contact with the killercells.

FIG. 12 depicts suppression of lymphocyte proliferation by regulatoryCD4+ T cells induced with TGF-β . Naïve CD4+ T cells from donor A weremixed with stimulator cells as described above and added to freshresponder and stimulator cells at the indicated ratios. The bars showthe uptake of tritiated thymidine±SEM after 7 days of culture. Thelightly shaded bar (Nil) indicates the proliferative response of theresponder T cells without added CD4+ cells. The darkly shaded barindicates the effect of control CD4+ cells which had been cultured withstimulator cells without TGF-β. The black bar indicates the effect ofCD4+ cells that had been mixed with stimulator cells in the presence ofTGF-β (1 ng/ml). The effect of these CD4+ cells on the proliferativeresponse of fresh responder cells added to irradiated stimulator cellsafter 7 days of culture is shown. The bars indicate the mean uptake oftritiated thymidine.

FIG. 13 depicts the regulatory activity of CD25+ CD4 T cells. CD4+ cellswere stimulated with irradiated allogeneic non-T cells +TGF-β (1 ng/ml)for 5 days. After washing, the CD4+ cells were stained with DII andfresh responder T cells were stained with carboxyfluorescein (CFSE).control or TGF-β primed CD4+ cells were added to the responder T cellsand allo-stimulator cells in a 1:4 ratio. After 5 days, the cells wereharvested and analyzed by flow cytometry. The intensity of CFSE in CD8+cells was determined by gating on DII negative cells. Note that theaddition of TGF-β primed CD4+ cells to responder T cells markedlydecreased cell division by CD8+ cells.

FIGS. 14A and 14B depict that regulatory CD4+ cells express CD25+ (IL-2)receptors on their surface. Control and TGF-β induced CD4+ regulatory Tcells were prepared as described above. After conditioning withallo-stimulator cells and TGF-β, the CD4+ cells were divided into CD25+and CD25− subsets by cell sorting and added to fresh responder T cellsand irradiated stimulator cells. The capacity of these responder cellsto kill stimulator T lymphoblasts is shown in a standard 4 hour chromiumrelease assay. In FIG. 14A, the open boxes show CTL activity withoutadditional CD4+ cells. Control or TGF-β induced regulatory T cells wereadded in a 1:4 ratio with responder cells. The open circles show thatthe control CD4+ cells did not alter CTL activity. The solid circlesshow that TGF-β induced CD4+ cells almost completely suppressed CTLactivity. The solid diamonds show that the suppressive activity wascontained exclusively in the CD25+ subset. The CD25− subset (solidsquares) did not have suppressive activity.

FIG. 14B shows the effect of decreasing the numbers of CD4+ regulatorycells added to the MLR. Decreasing the number to only 3% had a minimaleffect in decreasing the suppressive effects.

FIGS. 15A and 15B depict that repeated stimulation of T cells with a lowdose of staphylococcal enterotoxin B (SEB) induces T cells to produceimmunosuppressive levels of TGF-β. CD4+ T cells were stimulated with SEB(0.01 ng/ml) and irradiated B cells as superantigen presenting cellswith our without TGF-β at the times indicated by the arrows. ActiveTGF-β was measured 2 or 5 days later.

FIG. 16 depicts that repeated stimulation of CD4+ T cells with a lowdose of SEB enables these cells to produce immunosuppressive levels ofTGF-β. CD4+ T cells were stimulated with SEB (0.01 ng/ml) and irradiatedB cells as superantigen presenting cells with or without TGF-β at thetimes indicated by the arrows. Active TGF-β was measured 2 or 5 dayslater.

FIGS. 17A-17D show the effects of SEB on naive (CD45RA+ CD45RO−) CD4+and CD8+ T cells. The cells were stimulated with SEB every 5th day for atotal of three stimulations. The percentages of each T cell subset andthe cells expressing the CD25 IL-2 receptor activation marker weredetermined after each stimulation. FIGS. A and C show that if TGF-β 1ng/ml was included in the initial stimulation, CD4+ T cells became thepredominant subset in the cultures after repeated stimulation. FIGS. Band D show that CD25 expression by SEB stimulated cells decreases by thethird stimulation in control cultures. However, CD25 expression remainshigh if the T cells have been primed with TGF-β.

DETAILED DESCRIPTION

The present invention is directed to methods of treating autoimmunedisorders, including both cell-mediated and antibody-mediated disorderssuch as systemic lupus erythematosus (SLE). The methods involve removingcells from a patient and treating them with a composition that can actin one of two ways. In one embodiment, symptoms of antibody-mediatedautoimmune disorders are ameliorated using the compositions of theinvention. The compositions down-regulates B cell hyperactivity therebyinhibiting the production of antibodies, including autoantibodies,. Inaddition, the compositions enhance cell mediated immune responses thatare frequently defective in patients with SLE and certain otherantibody-mediated autoimmune disorders; that is, patients withantibody-mediated autoimmune disorders can be treated to amelioratetheir defective cell-mediated symptoms.

Alternatively, the compositions are used to treat cell-mediatedautoimmune disease. In this embodiment, the compositions induce immunecells to generate suppressor T cells. These suppressor T cells preventother T cells from becoming cytotoxic and attacking the cells and tissueof an affected individual. Thus, the composition decrease cytotoxicityand thereby ameliorate the symptoms of cell-mediated autoimmunedisorders.

This strategy is unlike almost all other treatment modalities currentlyin use which are either anti-inflammatory or immunosuppressive. Commonlyused corticosteroids suppress cytokine production and block the terminalevents which cause tissue injury, but generally do not alter theunderlying autoimmune response. Cytotoxic drugs or experimentalgenetically engineered biologicals such as monoclonal antibodies mayalso deplete specific lymphocyte populations or interfere with theirfunction. These drugs are generally only moderately successful and havesevere adverse side effects. Certain cytokines have been givensystemically to patients, but these agents also have broad actions withassociated serious adverse side effects.

By contrast, the strategy of the present invention is to produceremission by restoring normal regulatory cell function and, thus,“resetting” the immune system. Another significant potential advantageof this strategy is a low probability of serious adverse side effects.Since only trace amounts of regulatory compositions such as cytokineswill be returned to the patient, there should be minimal toxicity.

Circulating B lymphocytes spontaneously secreting IgG are increased inpatients with active SLE (Blaese, R. M., et al. (1980), Am J. Med69:345-350; Klinman, D. M. et al. (1991) Arthritis Rheum 34: 1404-1410).Sustained production of polyclonal IgG and autoantibodies in vitrorequires T cell help (Shivakumar, S. et al. (1989), J Immunol143:103-112). Previous studies of T cell regulation of spontaneous IgGproduction shows that while CD8+ T cells inhibit antibody production inhealthy individuals, in SLE these cells support B cell function instead(Linker-Israeli, M. et al. (1990), Arthritis Rheum 33:1216-1225). Inother autoimmune diseases such as rheumatoid arthritis and mutliplesclerosis, T cells rather than antibody are responsible for tissueinjury and the resulting inflammation (Panayi G S, et al. ArthritisRheum (1992) 35:725-773), Allegretta M et al. Science (1990)247:718-722.

Accordingly, in a preferred embodiment, the present invention is drawnto methods of treating antibody- and T cell-mediated autoimmune diseasesthat comprise removing peripheral blood mononuclear cells (PBMCs) fromthe patient with the autoimmune disease and treating certain of thesecells with an regulatory composition.

Without being bound by theory, it appears there are several ways themethods of the invention may work. First of all, the treatment of thecells by an regulatory composition leads to the direct suppression ofantibody production in the treated cells, which can lead to ameliorationof antibody-mediated autoimmune symptoms. Alternatively or additionally,the treatment of the cells induces regulatory cells to down regulateantibody production in other cells. Antibody in this context includesall forms of antibody, including IgA, IgM, IgG, IgE, etc. The net resultis a decrease in the amount of antibody in the system.

Additionally, the treatment of the cells enhances cell-mediated immuneresponses in patients with antibody-mediated autoimmune symptoms.Without being bound by theory, it appears that the treatment of thecells restores the balance between IL-10 and TNF-α leading to anenhanced production of Th1 cytokines and normalization of cell mediatedimmunity.

Furthermore, stimulation of immune cells with regulatory compositionsincluding TGF-β can suppress cell-mediated immune responses. Withoutbeing bound by theory, it appears that CD4+ T cells can be stimulated toproduce immunosuppressive levels of active TGF-β, that then suppressescell-mediated immune responses. Alternatively, CD4+ T cells can bestimulated to suppress the activation and/or effector functions of otherT cells by a contact-dependent mechanism of action. These effectsrequire CD4+ cells to be activated in the presence of TGF-β.

Thus, the present invention inhibits aberrant immune responses. Inpatients with antibody-mediated autoimmune disorders, the presentinvention restores the capacity of peripheral blood T cells to downregulate antibody production and restores cell mediated immune responsesby treating them with an regulatory composition ex vivo. In patientswith cell-mediated disorders, the present invention generates regulatoryT cells which suppress cytotoxic T cell activity in other T cells.

By “immune response” herein is meant host responses to foreign or selfantigens. By “aberrant immune responses” herein is meant the failure ofthe immune system to distinguish self from non-self or the failure torespond to foreign antigens. In other words, aberrant immune responsesare inappropriately regulated immune responses that lead to patientsymptoms. By “inappropriately regulated” herein is meant inappropriatelyinduced, inappropriately suppressed and/or non-responsiveness. Aberrantimmune responses include, but are not limited to, tissue injury andinflammation caused by the production of antibodies to an organism's owntissue, impaired production of IL-2, TNF-α and IFN-γ and tissue damagecaused by cytotoxic or non-cytotoxic mechanisms of action. Accordingly,in a preferred embodiment, the present invention provides methods oftreating antibody-mediated autoimmune disorders in a patient. By“antibody-mediated autoimmune diseases” herein is meant a disease inwhich individuals develop antibodies to constituents of their own cellsor tissues. Antibody-mediated autoimmune diseases include, but are notlimited to, systemic lupus erythematosus (SLE), pemphigus vulgaris,myasthenia gravis, hemolytic anemia, thrombocytopenia purpura, Grave'sdisease, dermatomyositis and Sjogren's disease. The preferred autoimmunedisease for treatment using the methods of the invention is SLE.

In addition, patients with antibody-mediated disorders frequently havedefects in cell-mediated immune responses. By “defects in cell mediatedimmune response” herein is meant impaired host defense againstinfection. Impaired host defense against infection includes, but is notlimited to, impaired delayed hypersensitivity, impaired T cellcytotoxicity and impaired production of TGF-β. Other defects, include,but are not limited to, increased production of IL-10 and decreasedproduction of IL-2, TNF-α and IFN-γ. Using the methods of the presentinvention, purified T cells are stimulated to increase production ofIL-2, TNF-α and IFN-γ and decrease production of IL-10. T cells whichcan be stimulated using the current methods include, but are not limitedto, CD4+ and CD8+. In one embodiment, antibody-mediated disorders arenot treated.

In a preferred embodiment, the present invention provides methods oftreating cell-mediated autoimmune disorders in a patient. By“cell-mediated autoimmune diseases” herein is meant a disease in whichthe cells of an individual are activated or stimulated to becomecytotoxic and attack their own cells or tissues. Alternatively, theautoimmune cells of the individual may stimulate other cells to causetissue damage by cytotoxic or non-cytotoxic mechanisms of action.Cell-mediated autoimmune diseases include, but are not limited to,Hashimoto's disease, polymyositis, disease inflammatory bowel disease,multiple sclerosis, diabetes mellitus, rheumatoid arthritis, andscleroderma. By “treating” an autoimmune disorder herein is meant thatat least one symptom of the autoimmune disorder is ameliorated by themethods outlined herein. This may be evaluated in a number of ways,including both objective and subjective factors on the part of thepatient. For example, immunological manifestations of disease can beevaluated; for example, the level of spontaneous antibody andautoantibody production, particularly IgG production in the case of SLE,is reduced. Total antibody levels may be measured, or autoantibodies,including, but not limited to, anti-double-stranded DNA (ds DNA)antibodies, anti-nucleoprotein antibodies, anti-Sm, anti-Rho, andanti-La. Cytotoxic activity can be evaluated as outlined herein.Physical symptoms may be altered, such as the disappearance or reductionin a rash in SLE. Renal function tests may be performed to determinealterations; laboratory evidence of tissue damage relating toinflammation may be evaluated. Decreased levels of circulating immunecomplexes and levels of serum complement are further evidence ofimprovement. In the case of SLE, a lessening of anemia may be seen. Theability to decrease a patient's otherwise required drugs such asimmunosuppressives can also be an indication of successful treatment.Other evaluations of successful treatment will be apparent to those ofskill in the art of the particular autoimmune disease.

By “patient” herein is meant a mammalian subject to be treated, withhuman patients being preferred. In some cases, the methods of theinvention find use in experimental animals, in veterinary application,and in the development of animal models for disease, including, but notlimited to, rodents including mice, rats, and hamsters; and primates.The methods provide for the removal of blood cells from a patient. Ingeneral, peripheral blood mononuclear cells (PBMCs) are taken from apatient using standard techniques. By “peripheral blood mononuclearcells” or “PBMCs” herein is meant lymphocytes (including T-cells,B-cells, NK cells, etc.) and monocytes. As outlined more fully below, itappears that in one embodiment, the main effect of the regulatorycomposition is to enable CD8+ or CD4+ T lymphocytes to suppress harmfulautoimmune responses. Accordingly, the PBMC population should compriseCD8+ T cells. Preferably, only PBMCs are taken, either leaving orreturning substantially all of the red blood cells and polymorphonuclearleukocytes to the patient. This is done as is known in the art, forexample using leukophoresis techniques. In general, a 5 to 7 literleukophoresis step is done, which essentially removes PBMCs from apatient, returning the remaining blood components. Collection of thecell sample is preferably done in the presence of an anticoagulant suchas heparin, as is known in the art.

In some embodiments, a leukophoresis step is not required.

In general, the sample comprising the PBMCs can be pretreated in a widevariety of ways. Generally, once collected, the cells can beadditionally concentrated, if this was not done simultaneously withcollection or to further purify and/or concentrate the cells. The cellsmay be washed, counted, and resuspended in buffer.

The PBMCs are generally concentrated for treatment, using standardtechniques in the art. In a preferred embodiment, the leukophoresiscollection step results a concentrated sample of PBMCs, in a sterileleukopak, that may contain reagents and/or doses of the regulatorycomposition, as is more fully outlined below. Generally, an additionalconcentration/purification step is done, such as Ficoll-Hypaque densitygradient centrifugation as is known in the art.

In a preferred embodiment, the PBMCs are then washed to remove serumproteins and soluble blood components, such as autoantibodies,inhibitors, etc., using techniques well known in the art. Generally,this involves addition of physiological media or buffer, followed bycentrifugation. This may be repeated as necessary. They can beresuspended in physiological media, preferably AIM-V serum free medium(Life Technologies) (since serum contains significant amounts ofinhibitors) although buffers such as Hanks balanced salt solution (HBBS)or physiological buffered saline (PBS) can also be used.

Generally, the cells are then counted; in general from 1×10⁹ to 2×10⁹white blood cells are collected from a 5-7 liter leukophoresis step.These cells are brought up roughly 200 mls of buffer or media.

In a preferred embodiment, the PBMCs may be enriched for one or morecell types. For example, the PBMCs may be enriched for CD8+ T cells orCD4+ T cells. This is done as is known in the art, as described in Grayet al. (1998), J. Immunol. 160:2248, hereby incorporated by reference.Generally, this is done using commercially available immunoabsorbentcolumns, or using research procedures (the PBMCs are added to a nylonwool column and the eluted, nonadherent cells are treated withantibodies to CD4, CD16, CD11b and CD74, followed by treatment withimmunomagnetic beads, leaving a population enriched for CD8+ T cells).

In a preferred embodiment, the PBMCs are separated in a automated,closed system such as the Nexell Isolex 300i Magnetic Cell SelectionSystem. Generally, this is done to maintain sterility and to insurestandardization of the methodology used for cell separation, activationand development of suppressor cell function.

Once the cells have undergone any necessary pretreatment, the cells aretreated with an regulatory composition. By “treated” herein is meantthat the cells are incubated with the regulatory composition for a timeperiod sufficient to develop the capacity to inhibit immune responses,including antibody and autoantibody production, particularly whentransferred back to the patient. The incubation will generally be underphysiological temperature. As noted above, this may happen as a resultof direct suppression of Antibody production by the treated cells, or byinducing regulatory cells to down regulate the production of antibody inthe patient's lymphoid organs.

By “regulatory composition” or “antibody production inhibitorcomposition” or “humoral inhibitor composition” or “non-specific immunecell inhibitor” or specific T cell inhibitor” or “inhibitorycomposition” or “suppressive composition” herein is meant a compositionthat can cause suppression of immune responses, including inhibition ofT cell activation, inhibition of spontaneous antibody and autoantibodyproduction, or cytotoxicity, or both. Generally, these compositions arecytokines. Suitable regulatory compositions include, but are not limitedto, T cell activators such as anti-CD2, including anti-CD2 antibodiesand the CD2 ligand, LFA-3, and mixtures or combinations of T cellactivators such as Concanavalin A (Con A), staphylococcus enterotoxin B(SEB), anti-CD3, anti-CD28 and cytokines such as IL-2, IL-4, TGF-β andTNF-α. A preferred regulatory composition for antibody suppression is amixture containing a T cell activator, IL-2 and TGF-β. The preferredregulatory composition for suppression of cytotoxicity is TGF-β.

The concentration of the regulatory composition will vary on theidentity of the composition. In a preferred embodiment, TFG-β is acomponent the regulatory composition. By “transforming growth factor-β”or “TGF-β” herein is meant any one of the family of the TGF-βs,including the three isoforms TGF-β1, TGF-β2, and TGF-β3; see Massague,J. (1980), J. Ann. Rev. Cell Biol 6:597. Lymphocytes and monocytesproduce the β1 isoform of this cytokine (Kehrl, J. H. et al. (1991), IntJ Cell Cloning 9: 438-450). The TFG-β can be any form of TFG-β that isactive on the mammalian cells being treated. In humans, recombinantTFG-β is currently preferred. A preferred human TGF-β can be purchasedfrom Genzyme Pharmaceuticals, Farmington, Mass. In general, theconcentration of TGF-β used ranges from about 2 picograms/ml of cellsuspension to about 5 nanograms, with from about 10 pg to about 4 ngbeing preferred, and from about 100 pg to about 2 ng being especiallypreferred, and 1 ng/ml being ideal.

In a preferred embodiment, IL-2 is used in the regulatory composition.The IL-2 can be any form of IL-2 that is active on the mammalian cellsbeing treated. In humans, recombinant IL-2 is currently preferred.Recombinant human IL-2 can be purchased from Cetus, Emeryville, Calif.In general, the concentration of IL-2 used ranges from about 1 Unit/mlof cell suspension to about 100 U/ml, with from about 5 U/ml to about 25U/ml being preferred, and with 10 U/ml being especially preferred. In apreferred embodiment, IL-2 is not used alone.

In a preferred embodiment, CD2 activators, such as a combination ofmitogenic anti CD2 antibodies, which may include the CD2 ligand LFA-3,are used as the regulatory composition. CD2 is a cell surfaceglycoprotein expressed by T lymphocytes. By “CD2 activator” herein ismeant compound that will initiate the CD2 signaling pathway. A preferredCD2 activator comprises anti CD2 antibodies (OKT11, American TypeCulture Collection, Rockville Md. and GT2, Huets, et al., (1986) J.Immunol. 137:1420). In general, the concentration of CD2 activator usedwill be sufficient to induce the production of TGF-β. The concentrationof anti CD2 antibodies used ranges from about 1 ng/ml to about 10 μg/ml,with from about 10 ng/ml to about 100 ng/ml being especially preferred.In some embodiments it is desirable to use a mitogen to activate thecells; that is, many resting phase cells do not contain large amounts ofcytokine receptors. The use of a mitogen such as Concanavalin A orstaphylococcus enterotoxin B (SEB) can allow the stimulation of thecells to produce cytokine receptors, which in turn makes the methods ofthe invention more effective. When a mitogen is used, it is generallyused as is known in the art, at concentrations ranging from 1 μg/ml toabout 10 μg/ml is used. In addition, it may be desirable to wash thecells with components to remove the mitogen, such as α-methyl mannoside,as is known in the art.

In a preferred embodiment, T cells are strongly stimulated withmitogens, such as anti-CD2, anti-CD3, anti-CD28 or combinations ofmonoclonal antibodies, or a specific autoantigen, if known, andanti-CD28 or IL-2 as a co-stimulator. ConA is also used to stimulate Tcells. The presence of TGF-β in the suppressive composition induces Tcells to develop potent suppressive activity. Repeated stimulation ofthe T cells with our without TGF-β in secondary cultures may benecessary to develop maximal suppressive activity.

In a preferred embodiment, the invention provides methods comprisingconditioning T cells, including, but not limited to CD8+ T or CD4+ Tcells, and other minor T cell subsets such as CD8⁻CD4⁻, NK T cells,etc., with TGF-β. These T cells prevent other T cells from becomingcytotoxic effector cells.

In a preferred embodiment, the invention provides methods comprisingconditioning CD4+ or CD8+ T cells with TGF-β to produce immunosuppresivelevels of TGF-β.

In a preferred embodiment, the invention provides methods comprisingconditioning CD4+ or CD8+ T cells with TGF-β to produce T cells thatsuppress by a contact-dependent mechanism.

In a preferred embodiment, the invention provides methods comprisingtreating naive CD4+ T cells with a stimulant such that said CD4+ cellsproduce immunosuppressive levels of active TGF-β. By “stimulant” isgenerally meant a generalized stimulant that triggers all T cells, suchas anti-CD2 or anti-CD3.

In a preferred embodiment, the invention provides methods comprisingstimulating naive CD4+ T cells in the presence of TGF-β to expand theCD4+ cell population.

In a preferred embodiment, the invention provides methods which decreaseproduction of IL-10 and correspondingly increase TNF-a production.

The regulatory composition is incubated with the cells for a period oftime sufficient to cause an effect. In a preferred embodiment, treatmentof the cells with the regulatory composition is followed by immediatetransplantation back into the patient. Accordingly, in a preferredembodiment, the cells are incubated with the regulatory composition for12 hours to about 7 days. The time will vary with the suppressiveactivity desired. For suppression of antibody production 48 hours isespecially preferred and 5 days is especially preferred for suppressionof cytotoxicity.

In one embodiment, the cells are treated for a period of time, washed toremove the regulatory composition, and may be reincubated to expand thecells. Before introduction into the patient, the cells are preferablywashed as outlined herein to remove the regulatory composition. Furtherincubations for testing or evaluation may also be done, ranging in timefrom a few hours to several days. If evaluation of antibody productionprior to introduction to a patient is desirable, the cells will beincubated for several days to allow antibody production (or lackthereof) to occur.

Once the cells have been treated, they may be evaluated or tested priorto autotransplantation back into the patient. For example, a sample maybe removed to do: sterility testing; gram staining, microbiologicalstudies; LAL studies; mycoplasma studies; flow cytometry to identifycell types; functional studies, etc. Similarly, these and otherlymphocyte studies may be done both before and after treatment.

In a preferred embodiment, the quantity or quality, i.e. type, ofantibody production, may be evaluated. Thus, for example, total levelsof antibody may be evaluated, or levels of specific types of antibodies,for example, IgA, IgG, IgM, anti-DNA autoantibodies, anti-nucleoprotein(NP) antibodies, etc. may be evaluated. Regulatory T cells may also beassessed for their ability to suppress T cell activation or to prevent Tcell cytotoxicity against specific target cells in vitro.

In a preferred embodiment, the levels of antibody, particularly IgG, aretested using well known techniques, including ELISA assays, as describedin Abo et al. (1987), Clin. Exp. Immunol. 67:544 and Linker-Israeli etal. (1990), Arthritis Rheum 33:1216, both of which are hereby expresslyincorporated by reference. These techniques may also be used to detectthe levels of specific antibodies, such as autoantibodies.

In a preferred embodiment, the treatment results in a significantdecrease in the amount of IgG and autoantibodies produced, with adecrease of at least 10% being preferred, at least 25% being especiallypreferred, and at least 50% being particularly preferred. In manyembodiments, decreases of 75% or greater are seen.

In a preferred embodiment, prior to transplantation, the amount of totalor active TGF-β can also be tested. As noted herein, TGF-β is made as alatent precursor that is activated post-translationally.

After the treatment, the cells are transplanted or reintroduced backinto the patient. This is generally done as is known in the art, andusually comprises injecting or introducing the treated cells back intothe patient, via intravenous administration, as will be appreciated bythose in the art. For example, the cells may be placed in a 50 mlFenwall infusion bag by injection using sterile syringes or othersterile transfer mechanisms. The cells can then be immediately infusedvia IV administration over a period of time, such as 15 minutes, into afree flow IV line into the patient. In some embodiments, additionalreagents such as buffers or salts may be added as well.

After reintroducing the cells into the patient, the effect of thetreatment may be evaluated, if desired, as is generally outlined above.Thus, evaluating immunological manifestations of the disease may bedone; for example the titers of total antibody or of specificimmunoglobulins, renal function tests, tissue damage evaluation, etc.may be done. Tests of T cells function such as T cell numbers,phenotype, activation state and ability to respond to antigens and/ormitogens also may be done.

The treatment may be repeated as needed or required. For example, thetreatment may be done once a week for a period of weeks, or multipletimes a week for a period of time, for example 3-5 times over a two weekperiod. Generally, the amelioration of the autoimmune disease symptomspersists for some period of time, preferably at least months. Over time,the patient may experience a relapse of symptoms, at which point thetreatments may be repeated.

In a preferred embodiment, the invention further provides kits for thepractice of the methods of the invention, i.e., the incubation of thecells with the regulatory compositions. The kit may have a number ofcomponents. The kit comprises a cell treatment container that is adaptedto receive cells from a patient with an antibody-mediated orcell-mediated autoimmune disorder. The container should be sterile. Insome embodiments, the cell treatment container is used for collection ofthe cells, for example it is adaptable to be hooked up to aleukophoresis machine using an inlet port. In other embodiments, aseparate cell collection container may be used.

In a preferred embodiment, the kit comprises a cell treatment containerthat is adapted to receive cells from a patient with a cell mediateddisorder. The kit may also be adapted for use in a automated closedsystem to purify specific T cell subsets and expand them for transferback to the patient.

The form and composition of the cell treatment container may vary, aswill be appreciated by those in the art. Generally the container may bein a number of different forms, including a flexible bag, similar to anIV bag, or a rigid container similar to a cell culture vessel. It may beconfigured to allow stirring. Generally, the composition of thecontainer will be any suitable, biologically inert material, such asglass or plastic, including polypropylene, polyethylene, etc. The celltreatment container may have one or more inlet or outlet ports, for theintroduction or removal of cells, reagents, regulatory compositions,etc. For example, the container may comprise a sampling port for theremoval of a fraction of the cells for analysis prior to reintroductioninto the patient. Similarly, the container may comprise an exit port toallow introduction of the cells into the patient; for example, thecontainer may comprise an adapter for attachment to an IV setup.

The kit further comprises at least one dose of an regulatorycomposition. “Dose” in this context means an amount of the regulatorycomposition such as cytokines, that is sufficient to cause an effect. Insome cases, multiple doses may be included. In one embodiment, the dosemay be added to the cell treatment container using a port;alternatively, in a preferred embodiment, the dose is already present inthe cell treatment container. In a preferred embodiment, the dose is ina lyophilized form for stability, that can be reconstituted using thecell media, or other reagents.

In some embodiments, the kit may additionally comprise at least onereagent, including buffers, salts, media, proteins, drugs, etc. Forexample, mitogens, monoclonal antibodies and treated magnetic beads forcell separation can be included.

In some embodiments, the kit may additional comprise writteninstructions for using the kits.

The following examples serve to more fully describe the manner of usingthe above-described invention, as well as to set forth the best modescontemplated for carrying out various aspects of the invention. It isunderstood that these examples in no way serve to limit the true scopeof this invention, but rather are presented for illustrative purposes.All references cited herein are incorporated by reference in theirentirety.

EXAMPLES Example 1 Treatment of PBMCs with a Mixture of IL-2 and TFG-β

Example 1 shows that the relatively brief treatment of PBMCs from SLEpatients with IL-2 and TFG-β can result in the marked inhibition ofspontaneous polyclonal IgG and autoantibody production. As discussedbelow, PBMC from 12 patients with active SLE were exposed to IL-2 withor without TGF-β for 3 days, washed and cultured seven more days. Themean decrease in IgG secretion was 79%. The strongest inhibitory effectwas observed in cases with the most marked B cell hyperactivity.Spontaneous production of anti-nucleoprotein (NP) antibodies wasobserved in 4 cases and cytokine treatment of PBMC decreasedautoantibody production by 50 to 96%. IL-2 inhibited antibody productionby either TGF-β-dependent or independent mechanisms in individualpatients. In a study of anti-CD2 stimulated IgG production in a patientwith active SLE, we documented that IL-2 and TGF-β can reverse theenhancing effects of CD8+ T cells on IgG production and inducesuppressive activity instead.

1. Methods Study Subjects for Spontaneous Antibody Synthesis

Twelve subjects were chosen with a diagnosis of SLE that fulfilled ARAcriteria for the classification of SLE (Arnett, F. C. et al. (1998),Arthritis Rheum 31: 315-324). These patients were all women, 8 Hispanic,2 African American, and 2 Asian. The age of each patient and duration ofdisease is shown in Table 1. Five patients were hospitalized and 7 wereoutpatients. Those patients who were receiving corticosteroids orantimalarials are also indicated. 8 patients were untreated. Diseaseactivity was assessed with SLAM (Liang, M. H. et al. (1989), ArthritisRheum 32:1107-1118) and SLEDAI (Bombardier, C. et al. (1992), ArthritisRheum 35:630-640) indices with mean values of 16.5 and 13.4respectively.

TABLE 1 Profile of SLE Patients Case SEX Age Ethnicity Duration 1 F 18AA 3 yr 2 F 37 H 6 mo 3 F 29 H 1 yr 4 F 32 AA 4 yr 5 F 57 A 5 mo 6 F 55H 5 mo 7 F 27 H 3 yr 8 F 21 H 2 yr 9 F 36 H 15 yr 10 F 41 A 4 yr 11 F 20H 6 yr 12 F 25 H 1 yr

Reagents

Recombinant TGF-β and monoclonal anti-TGF-β (1D11.16) antibody, a murineIgG1, were kindly provided by Dr. Bruce Pratt (Genzyme Pharmaceuticals,Farmington, Mass.). Recombinant IL-10 and monoclonal anti-IL-10(JES3-19F1) antibody, and control rat IgG2a, were kindly provided by Dr.Satwant Narula (Schering Plough Pharmaceuticals, Kenilworth, N.J.).Control murine IgG1 myeloma protein was purchased from Calbiochem, SanDiego, Calif. Recombinant human IL-2 was purchased from Chiron,Emmeryville, Calif. Anti-CD2 secreting hybridomas antibodies used OKT11were obtained from the American Type Culture Collection (ATCC),Rockville, MD and GT2 was generously provided by A. Bernard, Nice,France). Other antibodies included: anti-CD4 (OKT4, ATCC), anti-CD8(OKT8, ATCC; CD8, Dako, Carpenteria, Calif.), anti-CD11b (OKM1, ATCC),anti-CD16 (3G8), kindly provided by J. Unkeless, New York, N.Y.);anti-CD20 (Leu 16, Becton Dickinson, San Jose, Calif.) and anti-CD74(L243, ATCC).

Isolation of Blood Mononuclear Cells

Peripheral blood mononuclear cells (PBMC) were prepared from heparinizedvenous blood by Ficoll-Hypaque (Pharmacia, Piscataway, N.J.) densitygradient centrifugation. The mononuclear cells were washed in PBS with 5mM EDTA (Life Technologies, Grand Island, N.Y.) to remove platelets,which are a rich source of TGF-β.

Cell Culture Procedures

Procedures for cell cultures have been described previously (Wahl, S. M.(1994), J Exp Med 180:1587-1590; Gray, J. D. et al. (1998), J Immunol160:2248-2254). In brief, 2×10⁵ of PBMC were cultured in serum-freeAIM-V culture medium (Life Technologies) in the wells of 96-well flatbottom microtiter plate with or without the indicated cytokines. Afterthree days of culture, the PBMC were washed three times then freshserum-free medium was added. After a further 7 days at 37° C.,supernatants were harvested and assayed for total IgG and autoantibodiesreactive with calf thymus nucleoprotein (NP) by a solid phaseenzyme-linked immunoadsorbant assay (ELISA), as described previously(Linker-Israeli, M. et al. (1990), Arthritis Rheum 33:1216-1225). Theoptical density (OD) readings were transformed into units/ml (U/ml) froma standard curve using positive and negative standards. Supernatantsfrom PBMC culture of SLE patients (with high titers of anti-NPantibodies) and normal individuals were used as controls.

Statistical Analysis

The data were analyzed using Graph Pad, Prism software (San Diego,Calif.). We used analysis of variance (ANOVA) after log transformationof the data and the non-parametric Mann-Whitney test.

Anti-CD2 Induced IgG Synthesis.

The effects of CD8+ T cells cultured with or without NK cells onanti-CD2 stimulated CD4+ T cells and B cells was examined in a patientwith SLE in a normal control. CD4+ and CD8+ cells were prepared fromnylon non-adherent lymphocytes by negative selection usingimmunomagnetic beads as described previously (Gray, J. D. et al. (1998),J Immunol 160:2248-2254). For CD4+ cells the nylon non-adherent cellswere stained with antibodies to CD8, CD16, CD11b and CD74. The sameantibodies were used to obtain CD8+ cells except that CD4 wassubstituted for CD8. Purity of CD4+ cells was 95% and CD8+ cells 89%. Toobtain NK cells, PBMC were added to a nylon wool column and the eluted,non-adherent cells were immediately rosetted with AET treated sheep redblood cells. The non-rosetting fraction was then stained with anti-CD3and anti-CD74 (anti-HLA-DR) antibodies and depleted of reacting cellsusing immunomagnetic beads (Dynal). This resultant population contained98% CD56+ and <0.5% CD3+ and <0.5% CD20+ lymphocytes. Since SLE B cellsspontaneously secrete large amounts of IgG and because of the largeamount of blood needed to prepare sufficient numbers of B cells forthese studies, we substituted resting B cells from a healthy donor forpatient B cells in this study. To obtain B cells, nylon wool adherentcells were immediately rosetted with SRBC to remove any T cells, andtreated with 5 mM L-leucine methyl ester for complete removal ofmonocytes and functional NK cells. The resulting population was >92%CD20+ and <0.5% CD3+.

Results

In 12 patients studied, spontaneous IgG ranged from 0.4 to 13.7 μg/ml(FIG. 1). Exposure of PBMC to IL-2±TGF-β for 72 hours decreased IgGsynthesis in 8 of 12 cases studied by at least 50% (mean decrease 79%,p=0.008, Mann Whitney). The most dramatic decreases were observed incases with the most marked B cell hyperactivity. The correlation betweenthe amount of IgG secreted and percent inhibition by IL-2 and TGF-β wasr=0.647, p=0.02.

We compared the effects of IL-2 and TGF-β alone to the combination ofIL-2 and TGF-β. FIG. 2 shows that each of these cytokines also inhibitedIL-2 production. However, after log transformation to achieve a normaldistribution of the data and applying the Bonnferoni correction formultiple comparisons, analysis of variance revealed that only thecombination of IL-2 and TGF-β resulted in significant inhibition(p=0.05).

IL-10 production is increased in SLE (Llorente, L. et al. (1993), EurCytokine Network 4:421-427) and this cytokine can inhibit production ofboth IL-2 and TGF-β. In 9 cases we also assessed the effect ofanti-IL-10, but only a modest decrease of IgG synthesis was observed insome subjects and this difference was not statistically significant.Similarly, TNFα production is also decreased in a subset of patientswith SLE (Jacob, C. O. et al. (1990), Proc Natl Acad Sci 87:1233-1237).Although this cytokine also increases the production of active TGF-β(Ohtsuka, K. et al. (198), J Immunol 160:2539-2545), the addition ofTNFα to the cultures had minimal effects (results not shown).

We also examined SLE PBMC for spontaneous production ofanti-nucleoprotein (NP) autoantibodies and found significant titers in 4cases. In all cases exposure of PBMC to either IL-2 or IL-2 and TGF-βinhibited anti-NP production by at least 50 percent. TGF-β by itself wasineffective (Table 2). In these cases the effects of IL-2 by itself wasequivalent to that the combination of IL-2 and TGF-β.

TABLE 2 Effect of treating PBMC with IL-2 and TGF-β on SpontaneousAutoantibody production in SLE Anti-nucleoprotein antibody (U/ml)Cytokine Case Case Case Case treatment A: B: C: D: Nil 308 312 25 73TGF-β 282 298 26 ND (10 pg/ml) IL-2 & 29 14 12 35 TGF-β IL-2 23 10 11 ND*Percent of baseline values

PBMC from SLE patients were exposed to IL-2 (10 u/ml) and TGF-β (10pg/ml) for 72 hours. The cells were washed and cultured for sevenadditional days. Anti-NP released into the supernatants was measured byan ELISA.

Previously we have reported that IL-2 increases the production ofbiologically active TGF-β (Ohtsuka, K. et al. (1998), J Immunol160:2539-2545). It was, therefore, possible that al least some of theeffects of IL-2 on spontaneous antibody synthesis were mediated byTGF-β. This possibility was investigated by determining whether theeffects of IL-2 could be reversed by an anti-TGF-β neutralizingantibody. In the example shown in FIG. 3A, the addition of anti-TGF-βdid not affect spontaneous IgG synthesis. Antagonism of TGF-β, however,did abolish the inhibitory effects of IL-2 on IgG synthesis. PBMC fromthis patient (Case C in Table 2) also spontaneously produced anti-NPantibody. Here also anti-TGF-β abolished the inhibitory effects of IL-2on anti-NP production (FIG. 3B). In this subject, therefore, theinhibitory effects of IL-2 on spontaneous IgG and autoantibody synthesiswere mediated by TGF-β. This effect of anti-TGF-β was documented in 4 of8 cases studied. Thus, the inhibitory effects of IL-2 could either beTGF-β-dependent or independent. Examples of each effect are shown inTable 3.

TABLE 3 Effect of IL-2 and TGF-β on Spontaneous IgG Synthesis in SLEPatient A: Patient B: TGF-β TGF-β dependent inhibition independentinhibition Cytokines Added G (μgm/ml) IgG (μgm/ml) Medium only  2.5(100)*  2.6 (100) TGF-β (10 pg/ml) 1.4 (56) 2.5 (96) IL-2 & TGF-β 0.4(16) 0.5 (19) IL-2 & anti-TGF-β 11.6 (464) 0.5 (19) IL-2 & IgG1  3.6(144) 0.6 (23) *Percent of baseline IgG synthesis

We had the opportunity to repeat the study of on SLE patient 28 daysafter initiation of steroid therapy (Table 4). Before treatmentspontaneous IgG synthesis was greater than 2 μg/ml of IgG. Exposure ofPBMC to IL-2 markedly inhibited IgG production and TGF-β had a moderateeffect. Following corticosteroid therapy, spontaneous IgG productiondecreased by 75%. As before, exposure of PBMC to IL-2±TGF-β decreasedIgG production by 50%. However, this inhibition was reversed byanti-TGF-β. Here again, this effect of IL-2 could be explained byupregulation of endogenous active TGF-β.

TABLE 4 Effect of Corticosteroid Therapy on Spontaneous IgG Synthesis inSLE Before Treatment After Treatment Cytrokine Added Day 0 Day 28 Nil2.2 0.6 TGF-β (10 pg/ml) 1.2 0.4 IL-2 (10 U/ml) 0.4 0.3 IL-2 & TGF-β 0.70.3 IL-2 & anti-TGF-β ND 0.8 IL-2 & IgG1 ND 0.6 *Percent of baseline IgGsynthesis

In view of our previous studies in healthy subjects that IL-2 and TGF-βcan induce activated CD+ T cells to down-regulate antibody production,we attempted to isolate and treat CD8+ T cells from SLE patients in thisstudy. These experiments were unsuccessful because of the markedvariability of spontaneous antibody synthesis and the large amount ofblood required from patients with active SLE for cell separationprocedures. However, we were able to obtain enough blood from onepatient with active SLE to investigate the effect of IL-2 and TGF-β onCD8+ T cell modulation of anti-CD2 induced IgG synthesis. We haverecently reported that unlike anti-CD3, a mitogenic combination ofanti-CD2 monoclonal antibodies did not induce PBL to produce IgG (Gray,J. D. et al. (1998), J Immunol 160:2248-2254). An example is shown inFIG. 4A. This was because anti-CD2 stimulated NK cells to produce TGF-β,which in turn induced CD8+ T cells to down-regulate antibody production(Gray, J. D. et al. (1998), J Immunol 160:2248-2254). In this patient,as we have reported previously (Gray, J. D. et al. (1994), J Exp Med180:1937-1942), CD8+ T cells enhanced IgG synthesis and this enhancementwas markedly potentiated by the combination of NK cells and CD8+ T cells(FIG. 4B). By contrast IL-2 and TGF-β abolished the helper effects ofSLE CD8+ T cells and enabled these cells to suppress IgG production.This inhibitory effect of IL-2 and TGF-β was dependent upon the presenceof CD8+ T cells. (FIG. 4C). Thus, evidence has been obtained that theeffects of IL-2 and TGF-β can be mediated by CD8+ T cells.

These studies demonstrate that a short exposure of PBMC to IL-2 andTGF-β can greatly decrease subsequent spontaneous polyclonal IgG andautoantibody production in SLE, especially in patients with severedisease and marked B cell hyperactivity. This study confirms previousreports indicating that IL-2 can inhibit antibody production (Hirohata,S. et al. (1989), J Immunol 142: 3104-3112 and Fast, L. D. (1992), JImmunol 149:1510-1515) and reveals that picomolar concentrations ofTGF-β can contribute to this down-regulation. In the group of 12patients studied, the inhibitory effect of IL-2 and TGF-β on polyclonalIgG synthesis was greater than the effect of IL-2 alone. However, theinhibitory effects of IL-2 were heterogeneous. In 4 of 8 cases studied,the inhibition was TGF-β-dependent in that a neutralizing anti-TGF-β mAbabolished the effect. In the remaining cases the down-regulatory effectsof IL-2 were TGF-β-independent. Similarly, both TGF-β-dependent andindependent inhibition of spontaneous anti-NP autoantibody productionwas documented. We also investigated the effects of antagonizing theIL-10 and adding TNF-α because of previously described abnormalities inthe production of these cytokines in SLE (Llorente L. et al. (1993), EurCytokine Network 4:421-427; Jacob, C. O. et al. (1990), Proc Natl AcadSci 87:1233-1237). These procedures, however, had minimal effects onspontaneous antibody synthesis where lymphocytes had been activatedpreviously.

Others have reported that the degree of B cell hyperactivity in SLEcorrelates with disease activity (Blaese, R. M. et al. (1980), Am J Med69:345-350; Klinman, D. M. et al. (1991), Arthritis Rheum 34:1404-1410).This was not the case in the present study, possibly because ofconcurrent drug therapy. In general, those patients with markedspontaneous antibody synthesis were untreated whereas those with less Bcell activity were currently receiving prednisone. We presented one casewhere spontaneous IgG synthesis decreased markedly after corticosteroidtherapy was begun. This patient's B cells had also been secretinganti-NP antibody before treatment, and production of this autoantibodybecame undetectable after steroid therapy (result not shown).

TGF-βs consist of a multifunctional family of cytokines important intissue repair, inflammation and immunoregulation (Massague, J. (1990),Annu Rev Cell Biol 6597-641). TGF-β is different from most othercytokines in that it is secreted as an inert precursor molecule andconverted to its biologically active form extracellularly (Massague, J.(1990), Annu Rev Cell Biol 6597-641; Flaumenhaft, R. et al. (1993), AdvPharmacol 24:51-76). Regulatory T cells in various experimentalautoimmune models such as experimental autoimmune encephalitis (Weiner,H. L. et al. (1994), Annu Rev Immunol 12:809-837) and colitis (Neurath,M. F. et al. (1996), J Exp Med 183:2605-2516) produce this cytokine.TGF-β is immunosuppressive in nanomolar concentrations and can inhibit Tand B cell proliferation, NK cell cytotoxic activity and the generationof T cell cytotoxicity (Letterio, J. J. et al. (1998), Ann Rev Immunol16:137-162). By contrast, TGF-β has been reported to promote the growthof murine CD4+ cells and CD8+ cells (Kehrl, J. H. et al. (1986), J ExpMed 163:1037-1050; Lee, H. M. et al. (1993), J Immunol 151:668-677) andcan promote B cell differentiation (Van Vlasselaer, P. et al. (1992), JImmunol 148:2062-2067).

In our previous studies with lymphocytes from healthy subjects togenerate regulatory T cells, the picomolar concentrations of TGF-β usedwere smaller than that required for inhibition of T or B cell function(Gray, J. D. et al. (1998), J Immunol 160:2248-2254; Gray, J. D. et al.(1994), J Exp Med 180:1937-1942). Similar concentrations were used inthe present studies with SLE patients and TGF-β by itself had modestinhibitory effects on antibody synthesis. As before, a combination ofIL-2 of TGF-β produced the most potent inhibition. In our previousstudies, this effect was mediated by CD8+ T cells.

IL-2 has well established effects on the induction of T suppressor cellactivity (Hirohata, S. et al. (1989), J Immunol 142:3104-3112; Fast, L.D. J Immunol 149:1510-1515), but whether these effects are direct orindirect is unclear. In mice deletion of the IL-2 gene results inmassive lymphoproliferation and autoimmune disease (Sadlack, B. et al.(1995), Eur J Immunol 25:3053-3059). In SLE, a negative correlation wasreported between IL-2 levels and B cell hyperactivity (Huang, Y. P. etal. (1988), J Immunol 141:827-833).

Previously, we attempted to inhibit spontaneous antibody production inSLE with IL-2, but the results, however were extremely variable. Whilewe observed strong inhibition in some cases, in others IL-2 markedlyincreased antibody production. We believe that the timing and thecytokine milieu explains the more consistent inhibition observed in thisstudy. Here the IL-2 and TGF-β were present only during the initial 72hours of culture rather than the entire culture period. Enhancement ofantibody synthesis in the latter case could be explained by the positiveeffects of IL-2 on B cell differentiation (Coffman, R. L. et al. (1988),Immunol Rev 102:5-28). IL-2 can down-regulate antibody production byseveral mechanisms. In addition to the TGF-β circuit described in thereport, IL-2 induced inhibition can occur by up-regulation of IFN-γ(Noble, A. et al. (1998), J Immunol 160:566-571), or by cytolyticmechanisms (Stohl, W. et al. (1998), J Immunol 160:5231-5238; Esser, M.T. et al. (1997), J Immunol 158:5612-5618).

Previously, we had investigated the regulatory effects of NK cells onantibody synthesis and reported that while the direct effect of NK cellsis to up-regulate IgG synthesis (Kinter, A. et al. (1995), Proc Nat AcadSci USA 92:10985-10989), these lymphocytes have the opposite effect whencultured with CD8+ T cells in healthy subjects (Gray, J. D. et al.(1994), J Exp Med 180:1937-1942). In SLE patients, however, thecombination of CD8+ T cells and NK cells enhanced IgG production(Linker-Israeli, M. et al. (1990), Arthritis Rheum 33:1216-1225). Thiswas again observed in the present report. While in the normal subjectthe addition of NK cells to CD8+ T cells markedly inhibited anti-CD2stimulated IgG synthesis, the opposite was observed in SLE. From studiesof normals we had learned that NK cell-derived TGF-β inducedco-stimulated CD8+ T cells to down-regulate IgG and IgM production(Gray, J. D. et al. (1998), J Immunol 160:2248-2254). In this study IL-2and TGF-β induced moderate suppressive activity by CD8+ T cells. It islikely, therefore, that in SLE at least one way that IL-2 and TGF-βinhibit B cell activity is by generating regulatory T cells. Inaddition, other lymphocyte populations treated with these or othercytokines may also down-regulate B cells activity in SLE.

Example 2 1. The Correlation of TGF-β Production to Disease Activity andSeverity

Having shown that the lymphocyte production of the total and activeforms of TGF-β is decreased, we next asked whether these defectscorrelate with disease activity and/or severity. TGF-β1 production byblood lymphocytes from 17 prospectively studied SLE patients wascompared with 10 rheumatoid arthritis (RA) patients and 23 matchedhealthy controls. In RA the levels of active TGF-β1 were lower thancontrols, but not deceased to the extent found in SLE. Levels ofconstitutive and anti-CD2 stimulated active TGF-β1 detected in picomolaramounts were markedly reduced in 6 untreated patients hospitalized withrecent onset, very active and severe SLE and similarly reduced in 11patients with treated, less active disease. thus, decreased productionof active TGF-β1 did not correlate with disease activity. By contrast,decreased production of total TGF-β1 inversely correlated with diseaseactivity. Thus it appears that although impaired lymphocyte secretion ofthe latent precursor of TGF-β1 may result as a consequence of diseaseactivity, the ability to convert the precursor molecule to its activeform may be an intrinsic cellular defect. Insufficient exposure of Tcells to picomolar concentrations amounts of TGF-β1 at the time they areactivated can result in impaired down-regulation of antibody synthesis.Thus, decreased lymphocyte production of active TGF-β1 in SLE cancontribute to B cell hyperactivity characteristic of this disease.

2. Methods Study Subjects

Seventeen subjects with a diagnosis of SLE who fulfilled the AmericanCollege of Rheumatology criteria for the classification of SLE (Tan, E.M. et al. (1982), Arthritis Rheum 25:1271-1277), 10 subjects with RA whofulfilled the ACR 1987 revised criteria for the classification of RA(Arnett, F. C. et al. (1988), Arthritis Rheum 31:315-324), and 23healthy donors were studied. The SLE group consisted of 15 women and 2men (15 Hispanic, 1 African American, 1 Asian). The mean age was 34.5years (range, 20-75 years). Six patients were hospitalized, and 11 wereattending an outpatient clinic. All of the hospitalized patients wereuntreated before admission and were studied before they received theirfirst dose of corticosteroids. Outpatients were receiving less than 20mg of prednisone, and none were receiving cytotoxic drugs. Diseaseactivity was assessed with the SLAM (Liang, M. H. et al. (1989),Arthritis Rheum 32:1107-1118) and SLEDAI (Bombardier, C. et al. 1992),Arthritis Rheum 35:630-640) indices with mean values of 6.6 and 7.6,respectively. The RA group consisted of 9 women and 1 man (9 Hispanic, 1Asian). The mean age was 50.9 years (range, 39-67 years). All of thepatients were attending the outpatient clinic and had mild to moderatelyactive disease. The mean duration of disease was 9.5 years. One patientreceived myochrysine, 3 patients received prednisone (1, 1 and 20 mg), 3patients received methotrexate, and one patient received sulphasalazine.Healthy donors served as controls and were matched as closely aspossible for age, sex, and ethnic groups.

TABLE 5 Clinical Characteristics of Two Groups of SLE PatientsHospitalized Outpatient p Clinical Data (n = 6) (n = 11) Value Age 26.838.6 1.037 Sex (F/M) 6/0 9/2 Ethnic Group 5/0/1 10/1/0 (H/AA/A) DiseaseDuration 0.71 8.25 0.051 (yr) Disease Activity SLAM 13.3 2.9 0.014SLEDAI 15.7 4.1 0.006 Prednisone Dose 41.2 7.8 0.008 (mg/day) ActiveRenal 83% 9% 0.028 Disease Hemolytic 67% 9% 0.064 Anemia Anti-DNA(titer) 466.7 33.0 0.064 C3 47.5 98.6 0.008 C4 13.7 18.6 0.127

Reagents

Antibodies used were supernatants of hybridomas secreting anti-CD2(OKT11, American Type Culture Collection (ATCC), Rockville, Md., and GT2made available by Dr. Alain Bernard, Nice, France). A monoclonalantibody recognizing TGF-β isoforms 1,2 &3 (1D11), an antibody againstTGF-β isoforms 2&3 (3C7), and rTGF-β2 were kindly provided by Dr. BrucePratt (Genzyme Pharmaceuticals, Farmington, Mass.).

Isolation of Blood Lymphocytes

Peripheral blood mononuclear cells (PBMC) were prepared from heparinizedvenous blood by Ficoll-Hypaque (Pharmacia, Piscataway, N.J.) densitygradient centrifugation using methods described previously (Ohtsuka, K.et al. (1998), J Immunol 160:2539-2545). The mononuclear cells werewashed in PBS with 5 mM EDTA (Life Technologies, Grand Island, N.Y.) toremove platelets, which are a rich source of TGF-β. Peripheral bloodlymphocytes (PBL) were separated from PBMC by centrifugation through acontinuous Percoll (Pharmacia) density gradient. The percentage ofmonocytes remaining in the high density, lymphocyte-enriched fractionwas somewhat higher in SLE (8.5% vs 4.3%).

a) Cell Culture Procedures

Procedures for cell cultures have been described previously ((Ohtsuka,K. et al. (1998), J Immunol 160:2539-2545). In brief, 1×10⁵ of thelymphocytes were added to the wells of 96-well flat bottom microtiterplate (Greiner Rocky Mountain Scientific, Salt Lake City Utah). Thecultures were carried out in AIM-V serum free medium (LifeTechnologies), since serum contains significant amount of latent TGF-β.Anti-CD2 was used at the optimal concentrations to induce TGF-βproduction (GT2 1:40 and T11 1:80) hybridoma culture supernatants.Previous studies have revealed that anti-CD2 strongly stimulates PBL toproduce TGF-β (Gray, J. D. et al. (1998), J Immunol 160:2248-2254).

b) TGF-β Assay

Mink lung epithelial cells (MLEC) which had been transfected with anexpression construct containing a plasminogen activator inhibitor(PAI-1) promoter fused to luciferase reporter gene were kindly providedby Dr D. B. Rifkin, New York, N.Y. MLEC at 2×10⁴/well were incubatedwith 200 μl supernatants for 18 h at 37° C. To assay for luciferaseactivity, MLEC were lysed by a cell lysis reagent (AnalyticalLuminescence, Ann Arbor, Mich.). Cell lysates were then reacted withassay buffer and luciferin solution (both from Analytical Luminescence)immediately before being measured in a luminometer (Lumat, BertholdAnalytical Instruments Inc., Nashua, N.H.). To measure total TGF-βactivity, samples were heated at 80° C. for 3 minutes to release theactive cytokine from the latent complex. Active TGF-β activity wasmeasured without heating of supernatants. In all assays, severalconcentrations of rTGF-β were included to generate a standard curve. Thevariability of replicate cultures was less than 10 percent (Ohtsuka, K.et al. (1998), J Immunol 160:2539-2545).

c) Statistical Analysis

The significance of the results was analyzed using the Mann-Whitney testand Spearman rank correlation performed using GBSTAT software(Professional Statistics and Graphics Computer Program, DynamicMicrosystems Inc., Silver Spring, Md.).

d) Results

We measured constitutive and stimulated TGF-β1 produced by PBL frompatients with SLE or RA, and compared these values with those fromnormal controls. The cytokine detected in culture supernatants wasneutralized by a mAb recognizing isoforms 1,2,&3, but not by one againstisoforms 2&3, a result confirming the production of TGF-β1. Compared tonormal controls, constitutive production of active TGF-β1 wassignificantly decreased in SLE (14±5 vs 56±21 μg/ml, p=0.02, FIG. 5).Anti-CD2 stimulated active TGF-β1 was also decreased (87±22 vs 399±103pg/ml, p=0.003). In RA, the mean value for constitutive TGF-β1 wassimilar to that of SLE (19±5 pg/ml) and after stimulation by anti-CD2was intermediate between normal and SLE (197±54 pg/ml; FIG. 5).

Constitutive total TGF-β1 produced by lymphocytes was also decreased inSLE in comparison with the normal group (286±82 vs 631±185 pg/ml,p=0.05). The value in RA was intermediate between normal and SLE(435±161 pg/ml). Following the addition of anti-CD2, total TGF-β1increased in SLE somewhat more than in normal controls so that thedifferences were not statistically significant. Values in the RA groupwere again intermediate between the normal and SLE group.

To look for a possible relationship between decreased levels of TGF-β1and disease activity, we compared hospitalized SLE patients with thoseseen in the outpatient clinic. The clinical characteristics of these twogroups are summarized in Table 5. Those that were hospitalized wereyounger; 5 of 6 had symptoms for less than 3 months; they had markedlyactive disease; and most had severe SLE with nephritis and/or hemolyticanemia. The outpatient group by contrast, had chronic disease which hadbecome less active following treatment. Notwithstanding this markeddifference in disease heterogeneity, duration, activity, and severity,both constitutive and stimulated active TGF-β1 production weresignificantly decreased in both groups in comparison with normalcontrols (Table 6).

TABLE 6 Comparison of TGF-β1 Production by Lymphocytes from Two Groupsof Patients with SLE* SLE Normal Group 1 Group 2 (n = 23) (n = 6) (n =11) Active TGF-β1 (pg/ml) Constitutive 56 ± 21  21 ± 14† 10 ± 4† CD2 399± 103 117 ± 52†  70 ± 19‡ stimulated Total TGF-β1 (pg/ml) Constitutive631 ± 185 132 ± 44† 365 ± 120 CD2 stimulated 771 ± 136 226 ± 74† 667 ±166 *PBL 1 × 10⁵/well were cultured for 48 h, and the supernatants weretested for TGF-β1. SLE patients were divided into 2 groups. Group 1:Hospitalized patients. Group 2: Outpatient clinic patients. p valuesindicate comparison between the SLE group indicated and the normalcontrols as assessed by the Mann-Whitney test; †p < 0.05, ‡p < 0.01.

When we looked for correlations between levels of active and totalTGF-β1 with disease activity, there was a significant negativecorrelation between anti-CD2 stimulated production of total TGF-β1 andthe SLEDAI (r=−0.55, p=0.03, but not the SLAM index (−0.43, p=11). TheSLEDAI index is weighted for central nervous system involvement andrenal disease. Thus, an impaired capacity for lymphocytes to secrete theprecursor form of TGF-β1 appears to be associated with severe disease.

e) The Levels of Active TGF-β1 Did Not Correlate with Disease Activity.

The principal finding in this example is that decreased production ofactive TGF-β1 in SLE does not correlate with disease activity orseverity. Decreased amounts of constitutive and stimulated active TGF-β1were found in both patients with recent onset and established disease.Moreover, the values did not correlate with activity, as measured by theSLAM and SLEDAI indices, or severity as assessed by vital organinvolvement. However, while total TGF-β1 production was also decreasedin SLE, this defect appeared to correlate with disease activity. It wasfound chiefly in hospitalized SLE patients. The finding that totalTGF-β1 production correlated most strongly with the SLEDAI index, whichis weighted for major organ system involvement, also suggests arelationship with disease severity.

This study also included a control group of RA patients whose diseaseactivity was comparable to SLE patients with established disease.Although TGF-β1 values in the RA group was somewhat less than the normalcontrols, with the exception of constitutive active TGF-β1, themagnitude of the defect was not as marked as in SLE and was notstatistically significant.

Previously, we have documented that NK cells are the principallymphocyte source of TGF-β and the only lymphocyte population toconstitutively produce this cytokine in its active form (Gray, J. D. etal. (1998), J Immunol 160:2248-2254). It was of interest, therefore, tofind that constitutive production of NK cell-derived TGF-β was decreasedin SLE. We also learned that both IL-2 and TNF-α could enhance theproduction of active TGF-β. Production of both of these cytokines aredecreased in SLE (Gray, J. D. et al. (1994), J Exp Med 180:1937-1942).However, in most patients exogenous IL-2 and TNF-α could not restoreTGF-β production to normal (Example 2). IL-10 production is increased inSLE (Llorente, L. et al. (1993), Eur Cytokine Network 4:421) andcorrelations between elevated levels and disease activity have beenreported (Housslau, F. A. et al. (1995), Lupus 4:393-395; Haglwara, E.et al. (1996), Arthritis Rheum 39:379). IL-10 can inhibit IL-2, TNF-αand TGF-β production (Example 2 and Moore, K. W. et al. (1993), Ann RevImmunol 11:165-190). The findings that production of active TGF-β isdecreased in patients with mild as well as active disease, and that wecould only partially reverse the production defect by antagonizing IL-10(Example 2), suggests that increased IL-10 production, by itself, cannotaccount for decreased lymphocyte production of active TGF-β1 in SLE.Several mechanisms are probably involved. It is likely that one or moredefects in the extracellular conversion of the latent precursor to themature, active form may explain this abnormality.

Although TGF-β has well documented inhibitory properties on lymphocyteproliferation and effector cell function (Letterio, J. J. et al. (1998),Ann Rev Immunol 16:137-162), stimulatory properties have also beenreported (Lee, H. M. et al. (1991), J Immunol 151:668-677). TGF-βmodulates cytokine production by stimulated T cells as well asup-regulating its production. In mice, TGF-β1 selectively activates CD8+T cells to proliferate (Lee, H. M. et al. (1991), J Immunol151:668-677), and augments the maturation of naive cells to memory Tcells (Lee, H. M. et al. (1991), J Immunol 147:1127-1133). In humansTGF-β1 is a potent inducer of effector T cells (Cerwenka, A. et al.(1994), J Immunol 153:4367-4377). While large (nanogram/ml) quantitiesare required for immuno-suppressive effects, we have shown that onlysmall (picogram/ml) quantities are needed to co-stimulate CD8+ T cellsfor down-regulatory effects on antibody production (Gray, J. D. et al.(1998), J Immunol 160:2248-2254).

These studies suggest, therefore, that while impaired lymphocytesecretion of the latent precursor of TGF-β1 may result as a consequenceof disease activity, decreased active TGF-β1 production in SLE is morecomplex and may result from several different mechanisms. We haveproposed that programming naive T cells to down-regulate antibodyproduction requires the presence of pg/ml quantities of active TGF-β atthe time they are activated and have evidence to support this suggestion(Gray, J. D. et al. (1998), J Immunol 160:2248-2254). Therefore, a lackof picomolar amounts of active TGF-β in the local environment at acritical time could possibly account for ineffective T cell regulatoryfunction to control B lymphocyte activity in SLE.

Example 3 1. Treating SLE With Mitogens

In this example, IgG production is down regulated by treating the cellswith an regulatory composition comprising a mitogen such as acombination of mitogenic anti-CD2 monoclonal antibodies. Theseantibodies may be added in soluble form or immobilized on beads to crosslink receptors on T cells and NK cells. The cells are prepared asoutlined in the above examples, and then they are incubated withmitogens to augment the population of cells that down regulate antibodyproduction. Con A is available from Sigma (St. Louis, Mo.).

Although it is not known how anti-CD2 works, it is believed that theseantibodies induce NK cells in the PBMC preparation to secrete activeTGF-β (Ohtsuka, K. et al. (198), J Immunol 160:2539-2545); TGF-β thenacts on T cells to become antibody suppressor cells.

The cells are then washed, if necessary, and transplanted back into thepatient.

Example 4 1. Treating Cells With a Mixture of Cytokines and Mitogens

Cells are prepared as outlined above, and incubated with an regulatorycomposition comprising a mixture of mitogen and cytokine to inducepopulations of cells that down regulate antibody production. An exampleof this approach is shown in FIG. 4C. In this example, maximum inductionof suppression was obtained by treating CD4+ cells and CD8+ cells withCon A, IL-2 and TGF-β for.

For the preparation of regulatory T cells that will be transferred backto the patient anti-CD2 and/or anti-CD3 monoclonal antibodies will beused instead of Con A to activate T cells. The regulatory compositioncontains TGF-β with or without IL-2. The cells are incubated with thecomposition for 4 to 72 hours using standard incubation techniques in aclosed system such as the Nexell 300i.Magnetic

a) Cell Selection System.

Following incubation, the cells are washed with HBBS to remove anycytokine and mitogen in the solution. The cells are optionally furtherexpanded by culturing with anti-CD3±anti-CD28 immobilized on beads. Thecells are suspended in 200-500 ml of HBBS and reintroduced into apatient.

Example 5 1. Treating Cells to Normalize Cell-Mediated Immunity

Contributing to autoantibody production in SLE is an imbalance betweenIL-10 and TNF-β production. Levels of IL-10 are excessive and levels ofTNF-α are decreased (Llorente et al. 1995. J Exp. Med. 181:839-44)(Houssiau, F. A. et al., 1995. Lupus 4:393-5. (Ishida, H. et al. 1994. JExp. Med. 179:305-10) (Jacob, C. O. and McDevitt, H. O., 1988. Nature331:356-358). We have evidence that this imbalance is corrected bystrongly activating T cells in the presence of TGF-β and have recentlyelucidated the mechanism of action of this effect.

Purified T cells were prepared as outlined above, and incubated withConA and IL-2 with or without TGF-β. FIG. 6 shows that T cellstimulation in the absence of TGF-β, resulted in increased production ofIL-10. However, when TGF-β was added to stimulated T cells, IL-10production was blocked and production of TNF-α was increased. Inaddition, TNFR2 expression was increased significantly. Without beingbound by theory, It is believed that accelerated TNF-α signaling viaTNFR2 induced by TGF-β results in regulatory T cells that inhibitantibody production. Our results support this suggestion.

We have determined that upregulation of TNF-α by TGF-β is essential forthe induction of regulatory T cells. FIG. 7 shows two experiments wherethe addition of TGF-β to activated CD8+ T cells resulted in markedsuppression of IgG production. This suppressive activity depended uponTNF-α as an essential intermediate. In each of these experiments, aneutralizing anti-TNF-α antibody completely abolished the suppressiveeffects of the CD8+ regulatory T cells (CD8reg).

Patients with SLE have a marked defect in cell-mediated immunity withimpaired production of IL-2, TNF-α and IFN-γ. (Horwitz, D. A. et al.(1997), Dubois' Lupus Erythematosus, 5th Ed. (1997), pp. 83-96, D. J.Wallace et al. eds., Williams and Wilkins, Baltimore). Without beingbound by theory, it is believed that the defect in lymphocyte productionof TGF-β is partially responsible for impaired production of IL-2, TNF-αand IFN-γ. We have found that stimulation of T cells in the presence ofTGF-β significantly increased production of IL-2, TNF-α and IFN-γ whenthese cells were restimulated. Moreover, this result was dependent uponupregulation of TNF-α by TGF-β (see FIG. 8).

We have evidence that TGF-β production is decreased in SLE and that thisdefect contributes to the imbalance between IL-10 and TNF-α. Withoutbeing bound by theory, it is believed that high levels of IL-10 in SLEsustain autoantibody production and are responsible for decreasedproduction of TNF-α, IL-2, IFN-γ. Decreased production of thesecytokines is responsible for defective cellular immunity in SLE. We havedemonstrated that under specified conditions, TGF-β down-regulates IL-10and enhances the production of TNF-α. Down-regulation of IL-10 andenhancement of TNF-α production by TGF-β plays a crucial role in thenormalization of regulatory T cell activity in SLE, restoration ofcell-mediated immunity and remission of disease.

Example 6

1. Generation of Regulatory T Cells that Suppress Cell-MediatedAutoimmunity

The previous examples used regulatory compositions to treatantibody-mediated autoimmune diseases. Similar compositions are used toinduce CD4+ as well as CD8+ T cells to suppress cell-mediated autoimmunediseases. We show that CD8+ or CD4+ cells conditioned by TGF-β alonesuppressed the generation of T cell cytotoxicity. Instead of usingmitogens to induce regulatory T cells, the allogeneic mixed lymphocytereaction is used for this purpose. In this reaction, T cells from oneindividual recognize and respond to foreign histocompatibility antigensdisplayed by other individuals PBMCs. These responder T cellsproliferate and develop the capacity to kill these target cells. Todevelop suppressor T cells, various CD4+ and CD8+ T cell subsets fromone individual (donor A) were cultured with irradiated T cell-depletedmononuclear cells from another individual (donor B). The cells werecultured for 5 days with or without TGF-β (1 ng/ml) in the suspensions.After this time, TGF-β was removed and the cells added to fresh T cellsfrom donor A and non-T cells from donor B. FIG. 9 shows TGF-β inducedboth CD4+ and CD8+ T cell subsets to develop the capacity to inhibitcell mediated cytotoxicity. FIG. 10 shows two additional experimentswith CD4+ regulatory T cells induced by TGF-β.

Further studies revealed that regulatory CD4+ T cells generated in thismanner have a unique mode of action. Unlike the CD8+ and CD4+ T cellsgenerated previously which suppress by secreting inhibitory cytokines,these allo-specific regulatory CD4+ T cells have a contact dependentmechanism of action (FIG. 11). Without being bound by theory, it isbelieved that these regulatory T cells suppress other T cells from beingactivated. Addition of these T cells to responder T cells andallo-stimulator cells inhibited proliferation (FIG. 12) and decreasedthe ability of responder CD8+ killer precursor cells to become activated(FIG. 13).

We also learned that these regulatory CD4+ cells express IL-2 receptors(CD25) on their cell surface and were extremely potent (FIG. 14).Decreasing the proportion of regulatory CD4+ cells to responder T cellsfrom 1:4 (20%) to 1:32 (3%) only minimally decreased the inhibitoryeffects of these cells.

Because only a few of these cells are needed for potent down-regulatoryeffects, it is likely that a sufficient number can be transferred topatients to suppress autoimmunity or other desired immunosuppressiveeffects, such as inhibiting of graft rejection.

Example 7 1. Stimulating CD4+ T Cells to Produce ImmunosuppressiveLevels of TGF-β

CD4+ T cells that produce immunosuppressive levels of TGF-β have beennamed Th3 cells, but the mechanisms involved in their development arepoorly understood. We have obtained evidence that strong stimulation ofCD4+ cells with the superantigen, staphylococcus enterotoxin B (SEB), orrepeated stimulation of CD4+ cells stimulated with a lower concentrationof SEB induced these cells to produce immunosuppressive levels of activeTGF-β.

FIG. 15 shows increased production of both active and total TGF-βproduced by CD4+ T cells stimulated with increasing concentrations ofSEB. FIG. 16 shows the effect of repeated stimulation of CD4+ T cellswith low doses of SEB. By the third time these T cells were stimulatedwith SEB, they produced significant amounts of the active form of TGF-β.

FIG. 17 shows the effects of SEB on naive (CD45RA+CD45RO−) CD4+ and CD8+T cells. The cells were stimulated with SEB every 5th day for a total ofthree stimulations. The percentages of each T cell subset and the cellsexpressing the CD25 IL-2 receptor activation marker were determinedafter each stimulation. Panels A and C show that by including TGF-β 1ng/ml in the initial stimulation, CD4+ T cells became the predominantsubset in the cultures after repeated stimulation. FIGS. B and D showthat CD25 expression by SEB stimulated cells decreased by the thirdstimulation in control cultures. However, CD25 expression remained veryhigh if the T cells were primed with TGF-β. Thus, TGF-β appears to havepreferential effects on CD4+ cells if these T cells are repeatedlystimulated and almost all of these cells were CD25+ after culture for 20days. In summary, following T cell stimulation, the predominantregulatory effects of TGF-β are directed to CD8+ cells. Upon repeatedstimulation, this cytokine now induces CD4+ cells to become regulatorycells and these cells are more potent than CD8+ cells in theirsuppressive activities.

1. An isolated population of cells comprising at least 50%immunosuppressive regulatory T cells, wherein said immunosuppressiveregulatory T cells are CD4+ CD25+.
 2. The isolated population of cellsaccording to claim 1, wherein said CD4+ CD25+ immunosuppressiveregulatory T cells are antigen specific.
 3. The isolated populationaccording to claim 2, wherein said antigen is selected from: analloantigen and an autoantigen.
 4. The isolated population according toclaim 1, wherein said CD4+ CD25+ immunosuppressive regulatory T cellsare human.
 5. The isolated population according to claim 4, wherein saidCD4+ CD25+ immunosuppressive regulatory T cells are derived fromperipheral blood mononuclear cells (PBMC).
 6. A method of identifyingimmunosuppressive regulatory T cells in a sample comprising: screening Tcells in said sample to detect CD4+ CD25+ T cells; and identifying saiddetected CD4+ CD25+ T cells as immunosuppressive regulatory T-cells. 7.The method according to claim 6, wherein said method further comprisescontacting said sample to a regulatory composition prior to saidscreening step.
 8. The method according to claim 7, wherein saidregulatory composition comprises one or more of antigen, cytokines,cells and T cell stimulatory agents.
 9. The method according to claim 8,wherein said antigen is selected from: an alloantigen and anautoantigen.
 10. The method according to claim 8, wherein said cytokineis selected from: TGF-β, IL-2, and IL-15.
 11. The method according toclaim 8, wherein said cells are selected from: antigen presenting cellsand allogeneic cells.
 12. The method according to claim 8, wherein saidT cell stimulatory agents are selected from: anti-CD3 antibody,anti-CD28 antibody, anti-CD2 antibody and Concanavalin A.
 13. The methodaccording to claim 6, wherein said method further comprises isolatingsaid identified CD4+ CD25+ immunosuppressive regulatory T-cells.
 14. Themethod according to claim 13, wherein said method further comprisesexpanding said isolated CD4+ CD25+ immunosuppressive regulatory T-cellsby contacting said isolated CD4+ CD25+ immunosuppressive regulatoryT-cells to a T cell expansion composition.
 15. The method according toclaim 14, wherein said T cell expansion composition includes one or moreof: anti-CD3 antibody, anti-CD28 antibody, anti-CD2 antibody, IL-2,IL-15, antigen presenting cells, antigen and Concanavalin A.
 16. Themethod according to claim 6, wherein said sample is a peripheral bloodmononuclear cell (PBMC) sample.
 17. The method according to claim 6,wherein said CD4+ CD25+ immunosuppressive regulatory T-cells are human.18. A pharmaceutical composition for suppressing a pathological immuneresponse in a subject, wherein said pharmaceutical composition comprisesisolated immunosuppressive CD4+ CD25+ regulatory T cells.
 19. Thepharmaceutical composition according to claim 18, wherein said isolatedimmunosuppressive CD4+CD25+ regulatory T cells are antigen specific. 20.The pharmaceutical composition according to claim 20, wherein saidantigen is selected from: an alloantigen and an autoantigen.
 21. Thepharmaceutical composition according to claim 18, wherein saidimmunosuppressive CD4+ CD25+ regulatory T cells are derived from saidsubject.
 22. The pharmaceutical composition according to claim 18,wherein said immunosuppressive CD4+ CD25+ regulatory T cells are derivedfrom a donor.